Dominion means complete control or authority over something. When a king has dominion over a territory, he rules it completely. When you have dominion over your own room, you get to decide how it's organized and decorated.

The word suggests total power or sovereignty. In the Bible's creation story, God gives humanity dominion over the animals, meaning responsibility for caring for and managing them. A sea captain has dominion over her ship. A chess master might have dominion over the board, controlling the game so thoroughly that their opponent has few good moves left.

Dominion can also refer to the territory itself that someone controls. The British Dominion of Canada was a self-governing territory within the British Empire. A rancher's dominion might stretch across thousands of acres.

When someone has dominion, they're the one in charge, making the final decisions about what happens in that space or situation.